The present invention pertains generally to woodworking tools and particularly to devices for guiding a drill bit during a precise drilling operation as in the drilling of dowel receiving bores.
In woodworking, and particularly the joining of pieces by doweling, it is necessary that the pieces to be joined have axially alignable bores to receive a common dowel. Misalignment of bores results in both waste of time and materials. It is also important that dowel receiving bores be both properly spaced.
In the prior art, U.S. Pat. No. 2,798,520 discloses a drill guide providing a pair of drill guide tubes with a sight opening for registration with a marking on a workpiece. No provision is made on the guide to aid in holding same in place on the workpiece during a drilling operation. In drilling, especially hardwoods and large bore diameters, when the drill encounters variable resistance it tends to cause lateral shifting of a drill guide hence the guide shown in U.S. Pat. No. 2,798,520 would tend to move if not clamped. Further, the drilled bores are necessarily offset from a medial sight opening in the guide to prevent drilling on marked centers. The guide shown in the patent is not usable on large surface areas but rather is limited to edge surfaces.